World population trends

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Overview

It took hundreds of thousands of years for the world population to grow to 1 billion, and in just another 200 years or so it grew sevenfold. In 2011, the global population reached the 7 billion mark, and it is projected to climb to over 9 billion by 2050.

This dramatic growth has been driven largely by increasing numbers of people surviving to reproductive age, and has been accompanied by major changes in fertility rates, increasing urbanization and accelerating migration. These trends will have far-reaching implications for generations to come.

UNFPA helps countries identify and understand such trends, which are critical to development. UNFPA is one of the world’s largest funders of population data collection. UNFPA also advises countries that the best way to ensure sustainable development is to deliver a world where every pregnancy is wanted, every birth is safe, and every young person's potential is fulfilled.

News on World population trends

UNITED NATIONS, New York – “The world now has the largest generation of young people in history. I place great hope in their power to shape our future,” United Nations Secretary-General Ban Ki-moon told leaders and...

UNITED NATIONS, New York – Today, leaders from around the world opened the 48th session of the Commission on Population and Development, where they will take stock of the world's development and the welfare of its...

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Source: Estimates and UN Population Division: World Population Prospects: The 2012 Revision, online

Population prospects

The UN has developed three population projections, called variants – one high, one low, and one in between. Of these, the medium variant suggests that the world population will grow to about 10 billion by the middle of this century, and will level off at about 11 billion by the end of it. However, if fertility declines by less than assumed, the world population could grow to about 17 billion by the end of the century. If fertility falls by more than assumed, the world population could slightly fall over current levels to about 7 billion.

The UN publishes its population projections every two years, and over the past decades, the medium variant of the projections has often been corrected upward, meaning the population has grown more quickly than expected. The most recent upward correction was due to a slower fertility decline than anticipated in countries in sub-Saharan Africa and South Asia, as well as higher-than-expected levels of fertility in large and populous countries of Asia.

In addition, the world is seeing high levels of urbanization and accelerating migration. 2007 was the first year in which more people lived in urban areas than in rural areas, and by 2050 about 66 per cent of the world population will be living in cities.

These megatrends have far-reaching implications. They affect economic development, employment, income distribution, poverty and social protections. They also affect efforts to ensure universal access to health care, education, housing, sanitation, water, food and energy. To more sustainably address the needs of individuals, policymakers must understand how many people are living on the planet, where they are, how old they are, and how many people will come after them.

Why is the population growing so quickly?

The huge growth in the world population over the past two centuries is largely the result of advances in modern medicines and improvements in living standards. These have significantly reduced infant, child and maternal mortality, contributing to an increase in life expectancy. Although fertility levels have declined, they have not fallen at the same pace as mortality levels.

The world population will continue to grow for decades to come. This is the result of ‘population momentum’: Because of improved survival rates and past high fertility levels, there are more women of reproductive age today. This will contribute to a relatively large number of births, even if those women have fewer children on average. Although population growth is, today, largely attributable to population momentum, after 2060 it will almost exclusively be driven by fertility levels in the world’s least developed countries.

A varied landscape

General population trends mask considerable differences between countries. On the one side stand the world’s least developed countries, which continue to have high fertility levels. According to conservative projections, the population of the world’s least developed countries will double by 2050, and in some countries it will even triple. On the other side are high-income and rising-income countries, which are experiencing slow population growth or no population growth at all. Whereas the former continue to have large, growing, populations of young people, the latter have large, growing populations of older persons. (There are some countries experiencing a decline in population size. However, in most cases this is not only the result of low fertility, but also the result of high mortality and emigration due to weak and deteriorating economic, social and political conditions.)

While demographics vary considerably at national levels, the overall trends have global implications for sustainable development. The global climate will change no matter where greenhouse gases are emitted, for example. Efforts to sustainably meet the needs and desires of a growing world population will have implications for all countries – as will failure to meet these needs.

While surges in population will bring challenges, they also represent humanity's success. The move from higher to lower mortality and fertility reflects achievements in health, education and human rights. Falling fertility levels also create opportunities for countries to realize a demographic dividend – the economic growth that can occur when there is an increase in the number of people of working age and a decrease in the number of dependents.

Human rights

Population dynamics can be shaped by policies. But these policies must strengthen, rather than weaken, fundamental human rights and freedoms. Population dynamics are the cumulative result of individual choices and opportunities, and they are best addressed by enlarging these choices and opportunities – especially those related to sexual and reproductive health and rights. When couples can freely decide the number, timing and spacing of their children, evidence shows more children survive and thrive, and overall fertility levels trend downward.

Sexual and reproductive health and rights also make an enormous difference in the health and lives of all people, especially women, by dramatically reducing maternal and infant mortality rates, helping to prevent the spread of communicable diseases such as HIV, and empowering women to live more self-determined lives.

Publications on World population trends

Young people matter. They matter because an unprecedented 1.8 billion youth are alive today, and because they are the shapers and leaders of our global future. They matter because they have inherent human rights that...

Resources on World population trends

Population trends and dynamics play a powerful role in development, and must therefore be factored into planning and policy decisions. Population size and structure impact a country’s economy as well as its ability to...

UNITED NATIONS, New York, 18 November 2014—Developing countries with large youth populations could see their economies soar, provided they invest heavily in young people’s education and health and protect their rights,...